Can Only Reach Google and YouTube, Other Sites Can Not Connect

Hi, Xfinity Support,

Recently we have had issues with our WiFi network at home.  Sometimes, we can only reach google and youtube sites, but most other website we cannot connect.  I search the forum, and this thread sounds like the exact same problem.

https://forums.xfinity.com/conversations/your-home-network/only-access-to-google-and-youtube-some-devices-no-internet-even-though-it-shows-connects-cannot-connect-nest-ring-security/620319cee5fd17166fe51399

This seems to be a common issue with Xfinity.

The issue seems to happen around 8 to 10 pm every night, but that is not always the case.  Someone mentioned it is IPv4 and IPv6 issue, but so far I have not found a good, reliable solution.

Could someone please provide some help?  I have not restarted the router many times, when the issue happens, sometimes it "fixes" the issue for a while, sometimes it does not.  I have changed the DNS server to google's 8.8.8.8 and 8.8.4.4.  That seems to help in the beginning, but then same issue starts to happen again.

Thank you very much.

TJ